180° and 90° phase shifting networks with an octave bandwidth and small phase errors

Abstract

A new phase shifting network for both 180° and 90° phase shift with small phase errors over an octave bandwidth is presented. The theoretical bandwidth is 67% for the 180° phase bit and 86% for the 90° phase bit when phase errors are ±2°. The proposed topology consists of a bandpass filter (BPF) branch, consisting of a LC resonator and two shunt quarter-wavelength transmission lines (TLs), and a reference TL. A theoretical analysis is provided and scalable parameters are listed for both phase bits. To test the theory, phase shifting networks from 1 GHz to 3 GHz were designed. The measured phase errors of the 180° and the 90° phase bit are ±3.5° and ±2.5° over a bandwidth of 73% and 102% while the return losses are better than 18 dB and 12 dB, respectively. © 2006 IEEE.